Arm for a chair



FIG. 1 is a front perspective view of the arm for a chair embodying the new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

FIGS. 1-6 show an arm for a chair in broken lines. The portions shown in broken lines are for environmental purposes only and form no part of the claimed design. 

CLAIM The ornamental design for an arm for a chair, as shown and described. 